Ni-Ti-O混合氧化物的制备、表征及其富氧选择性催化还原NO

Preparation and characterization of Ni-Ti-O mixed oxide for selective catalytic reduction of NO under lean-burn conditions

采用均匀共沉淀法制备了不同Ni/Ti摩尔比的Ni-Ti-O混合氧化物,考察了它们在富氧条件下丙烯选择性催化还原NO反应中的催化性能,并运用X射线衍射,N2吸附-脱附、吡啶吸附、程序升温脱附和原位红外光谱对催化剂进行了表征.结果表明,Ni/Ti摩尔比为1的催化剂表现出最佳催化活性,430°C时NOx转化率达68%.该催化剂具有锐钛矿结构,比表面积较高(149m2/g),有利于提高催化活性;其表面Lewis酸性位有利于硝酸盐物种的吸附,而硝酸盐物种是该反应的重要中间体.

A novel Ni‐Ti‐O mixed‐oxide catalyst was prepared by a homogeneous coprecipitation method and tested in the selective catalytic reduction of NO by propene （C3H6‐SCR） in the presence of excess O2 . Catalysts with different molar ratios of Ni‐Ti were characterized using X‐ray diffraction, N2 adsorption‐desorption, pyridine adsorption, temperature‐programmed desorption, and in‐situ Fourier‐transform infrared spectroscopy. The Ni1Ti1 catalyst showed good activity in C3H6 ‐SCR at 430 ℃ and the NOx conversion achieved 68%. This catalyst displayed an anatase structure and had a high surface area （149 m2/g）, which is helpful to enhance the catalyst activity. Lewis acid sites were beneficial for adsorbing nitrate, which was the main intermediate produced during the SCR of NO by C3H6 .